1. Field of the Invention
The present invention relates to an antenna and, more particularly, to a multiband antenna which is able to cover multiband operation in mobile communication devices.
2. Description of the Related Art
Recently, various kinds of wireless communication applications emerge with the development and improvement of wireless communication technologies, such as laptop computers combined with wireless communication capabilities. For the present, most laptop computers are capable of wireless local area network (WLAN) operation. However, in order to provide more functionalities, laptop computers should be equipped with antennas capable of multiband operation to cover the wireless wide area network (WWAN) operation as well.
The WLAN antennas used in prior-art laptop computers are mostly inverted-F antennas, which bring challenges to engineers because of their sizes when they are applied for WWAN operation. In the prior art technique such as that disclosed in the Taiwan Patent No. I293215 entitled “Dual-Band Inverted-F Antenna”, a dual-band antenna uses a ground plane formed by a supporting metal frame of a LCD panel to achieve dual-band operation. However, the antenna is only suitable for WLAN operation. When the antenna is applied for multiband WWAN operation, it is difficult to be embedded inside a mobile communication device because the antenna will have a large size.
Therefore, in view of the deficiencies of prior-art techniques, it is necessary to provide a multiband antenna suitable to solve the problem presented in the prior art techniques.